Chemical weapons for use by the military, in which a chemical agent harmful to the human body is charged into the interior of a steel outer shell, are available conventionally in the form of artillery shells, bombs, landmines, underwater mines, and so on, for example. A treatment method employing blasting is known as a treatment method for rendering such chemical weapons harmless. When a blast treatment method is used, an operation for dismantling the chemical weapon is not required, and therefore this method can be applied to treat not only well-preserved chemical weapons but also chemical weapons that cannot be dismantled easily due to deterioration over time, deformation, and so on. Another advantage of this method is that substantially all of the chemical agent can be decomposed in an ultra-high temperature field and an ultra-high pressure field generated by an explosion. Patent Document 1 described below, for example, discloses an example of this type of blast treatment method.
In the blast treatment method disclosed in Patent Document 1, chemical ammunition in which an explosive and a chemical agent are housed in an outer shell serves as a treatment subject. ANFO explosive is disposed on an outer periphery of the treatment subject, and a sheet-form explosive having a higher detonation velocity than the ANFO explosive is disposed on an outer periphery of the ANFO explosive. The treatment subject is then blasted by initiating the sheet-form explosive from one axial direction side of the treatment subject such that the ANFO explosive on the inside of the sheet-form explosive explodes in response to detonation of the sheet-form explosive. At this time, the explosive in the interior of the treatment subject also explodes, causing the outer shell of the treatment subject to rupture such that the chemical agent in the interior is exposed. The chemical agent is decomposed and rendered harmless by detonation energy from the respective explosives.
Incidentally, treatment subjects include chemical ammunition in which only a chemical agent is charged into the interior of the outer shell, degraded ammunition in which a burster has deteriorated such that it is difficult to initiate, and so on. When these types of treatment subjects are blasted using the blast treatment method of Patent Document 1, it may be impossible to obtain explosive force from the interior of the treatment subject, or the explosive force from the interior of the treatment subject may be so small that the outer shell of the treatment subject does not rupture sufficiently, and as a result, the chemical agent may not be decomposed sufficiently.
Note that the outer shell may be ruptured sufficiently by increasing an amount of explosive disposed on the outer periphery of the treatment subject, but in this case, a cost increase occurs. Moreover, increases in the amount of explosive are limited due to safety considerations.    Patent Document 1: Japanese Patent Application Publication No. 2005-291514